Methanol steam reforming to hydrogen and carbon dioxide is catalyzed over Cu/ZnO prepared by a coprecipitation method. The addition of zirconium ions to the starting material of the catalyst results in improvement of the activity and reduction in the particle sizes of copper and zinc oxide. However, the surface activity of copper on Cu/ZnO/ZrO(2) is similar to that for Cu/ZnO. It is suggested that the activity depends mainly on the interaction between Cu and ZnO particles and the presence of zirconium oxide does not directly affect the activity. Steep deactivation occurs over Cu/ZnO in the reaction at 400 degrees C, but the presence of ZrO(2) particles hampers the aggregation and/or sintering of Cu and ZnO particles and mitigates the deactivation. (C) 2011 Elsevier B.V. All rights reserved.